Substation telephone set



J. ERECKSON.

SUBSTATION TELEPHONE SET.

APPLICATION FILED NOV. 10. 1915.

Patented A r. 5, 1921 UNITED stares,

PATENT. OFFICE.

JOHN ERICKSON, OF UHICAGO, ILLINOIS, ASBIGNOB TO AUTOHA'I'IC lmncrnrc GOI- PANY, OF CHICAGO, ILLINOIS, A CORPORATION 01' ILLINOIS.

SUBSTA'IION TELEPHONE SET.

Specification of Letters Patent.

Patented Apr. 5, 1921.

To allwhomitma concern:

Be it known t at I, Join: ERIGKSON, a citizen of the United States of America, and a resident of Chicago, county of Cook, and btate of Illinois, have invented certain new and useful Improvements in Substation Telephone Sets, of which the following is a plicating the substation apparatus, which is" very objectionable in any case, and particularly so in the case of substation equipment for use on rural lines. Again, the subscribers themselves 'usually view with disfavor any attempt to restrict their free use of the telephone, as is done in lock-out systems, even though aware that a better service mi ht result therefrom.

11 view of these considerations, I prefer not to use any positive lock-out device, but to trust rather to a sense of courtesy on the part of the subscribers; and in acordance with this idea, I so design the substations that the subscribers thereat are enabled to listen in on the line to observe its idle or busy condition without interfering with a call that may be in progress at the time. Being thus severally charged with responsibility for the service, the subscribers will seldom deliberately or maliciously interfere with each other.

In attaining the foregoing objects, I employ a simple mechanical device associated with the receiver hook at each substation, together with suitable circuits; all of which will be described and explained-fully hereinafter, reference being had to the accompanying drawings.

In the drawings, Figure 1 shows 111 in vention applied to a wall type telep one, Figs. 2 and 2 show a modification of the invention applied to a desk type telephone, while Fig. 3 is a circuit diagram applicable either to ig. 1 or to Fig. 2.

Referring now to Fig. 1, a sectional portion of the box of a wall telephone is indi cated by the reference character 2. A

bracket 3, on the inside, and an escutcheon plate 4, on the outside, are mounted on the box by means of machine screws 5 and 6. A right-angled plece 10 is pivotally mounted on the bracket 3 b means of the pin 9. The bracket? is doub e, as is also the piece 10, they both bemg formed from symmetrical flat punchm s, and the latter fits closely within the s1 es of the bracket. The detachable recelver hook H is clamped between the two sides of the fivoted piece 10 by means of the screw 11. 1; will be observed that the end of the hook is slotted so that when the screw 11 is loosened it can be removed. The contact sprmgs 20-24, inclusive, are mounted on a downwardly extendin portion of the bracket 3 and are control ed by the receiyer hook, the piece 10 being provided with a roller which en ages the spring 23.

The lever 7 is a stamping U section, like the bracket 3, and is pivoted on the receiver hook by a rivet 8. The lower end of the lever 7 is held away from the side of the box by a spring 13, whereby the projection 12, at the upper end, is enabled to engage the top of the slot in the escutcheon plate 4.

Reference will now be had to the circuit diagram Flgf 3 for an explanation of the operation. he line conductors 25 and 26 are assumed to extend to the exchange and terminate there in an individual switch in the usual and well known manner. It is to be understood also that a plurality of substations similar to the one shown in Fig. 3 are connected in bridge of the line conductors, but since the substations are all alike, but one of them has been shown.

When the receiver is on the hook the contact springs 23 and 24 are together, as seen in Fig. 3, and the ringer K is connected in bridge of the line as follows: line conductor 25, condenser C, contact springs 23 and 24, and the ringer K to line conductor 26. When the receiver is taken off the hook to initiate a call, the hook is raised by the spring 23 until the projection 12 engages the top of the slot in the escutcheon plate 4. In this position of the hook, the listening position, the contact springs 23 and 24 are separated and the former is in engagement with the contact spring 22, as shown clearly in Fig. l. A circuit including the receiver It may now be traced over the following path: line conductor 25, condenser 0, contact springs 23 and 22, secondary winding S of the induction coil, receiver R, and the callin device springs I to the line conductor 26. he calling subscriber is now supposed to listen in his receiver to see whether or not the line is in use. Since the receiver R is brid ed'across the line conductors in series with the condenser C and since the transmitter circuit is still open, another subscriber who is making a call or who is engaged in conversation will not be interfered with.

Assuming the line to be idle, the subscriber will now push in on the lower end of the lever 7 thereby disengaging the projection 12 from the slot in the escutcheon plate 4 and permitting the receiver hook to rise to its final position. The four contact springs 2023, inclusive, are now in engagement, with the result that the condenser C.

in the receiver circuit is short-circuited and the transmitter circuit is closed as follows: positive pole of battery B, contact springs 21 and 22, transmitter T, and the primary winding P of the induction coil to the negative pole of battery B. The substation is now in condition for talking.

Connection is extended to the called line by manipulating the calling device CD which may be of the general type of calling device disclosed in the British patent to C. G. S. Dicker, No. 29654 of 1910. Calling devices, or impulse senders, as they are sometimes termed, of the foregoing general ty e are well understood and need not be oi escribed in detail. It may be mentioned, however, that the calling device is preferabl provided with a pair of shunt springs closed as soon as the dial is moved from its normal position, whereby the impulse springs I may be included in a direct bridge of the line conductors.

I will now explain a modified form of the invention, reference being had to Figs. 2 and 2*. Fig. 2 shows a vertical section of a desk telephone which comprises essentially a tubular stand 30, mounted on a base 31, and supporting at its upper extremity a transmitter head 32. Fig. 2 is a horizontalsection of the transmitter head taken on the line Z. To proceed, the lower cylindrical portion of the head 32 fits inside the tubularstand 30 and has a vertical hole 33 and a transverse slot 34 to provide room for the receiver hook H and its accessories. The hook H is pivoted at35 in an obvious manner and controls the contact springs 20-24, inclusive, by means of the rod 37. A finger lever 39 is attached to the end of the hook bythe pivot 40 and projects through aslot in the tubular stand 30.. A cross piece 36 closes the transverse slot 34 in the head 32 at a point slightly below the downwardly proiecting end 4l of the finger lever 39.

In the drawing the receiver hook -is shown in its normal position, it being assumed that the receiver is hung up. When the receiver is removed, the hook is raised by the spring 42, carried on the rod 37 at the lower end thereof. As the right hand end of the hook moves downward under the influence of the spring 42, the finger lever 39'is caused to rotate about the pivot lever 39, thereby disengaging the projection 41 from the cross piece 36. The receiver hook is thus permitted to rise the rest of the way to close the contact springs 20--23, inclusive, whereby the receiver and transmitter circuits are closed for talking.

Having described my invention what I consider to be new and desire to have protected by Letters Patent will be pointed out in the a ended claims.

What claim as my invention is:

1. In a telephone system, a substation telephone set having ringing, talking, and listening circuits, a switch hook and contact springs controlled thereby, a condenser, said hook effectivein one position to close said ringing circuit including said condenser, in another position to close said talking circuit and to short circuit said condenser and in an intermediate position to close said listening circuit including said condenser, and a device effective when the receiver is removed to stop said hook in its intermediate position.

2. In a substation telephone set, a pair of line conductors, a hook switch, a bridge of said conductors including a signal, closed when the receiver is on the hook, means for stopping the hook switch in an intermediate position when the receiver is removed, a second bridge closed in the intermediate position of the hook and including a condenser and a receiver, means for permitting the said hook to pass its intermediate position, and means for then short-circuiting said condenser.

3. In a substation telephone set, a switch hook having upper, lower, and intermediate positions, a circuit includinga signal and a condenser closed in the lower position of said hook, a second circuit including a re-. ceiver and said condenser closed in the intermediate position, and a shunt circuit for said condenser closed in the upper posi-, tion.

4. In a substation telephone set, a hook switch having normal, ofi normal, and intermediate positions, transmitter and receiver circuits open in the normal position of said switch, means for closing a receiver circuit in the intermediate position of said switch and for closing said transmitter circuit and closing a new receiver circuit only in its oil normal position, and a pawl pivoted to said hook for automatically stopping the same in its intermediate position when the receiver is removed.

5. In a substation telephone set, a hook switch having normal, 011' normal, and intermediate positions, transmitter and receiver circults open in the normal position of said switch, means for closing a receiver circuit in the intermediate position of said switch and for closing said transmitter circuit and closing a new receiver circuit only in its oil normal position, and a trigger mounted on said hook and cooperating with a fixed stop to retain said hook in its intermediate position. Y

6. In a substation telephone set, the combination with a hook switch, of a listening circuit, .and a talking circuit controlled by said hook switch, said hook switch having three positions, means for moving said hook switch from first to second position to close said listening circuit and for. moving said switch hook from second to third position to render said listening circuit inoperative and to close said talking circuit.

7 In a substation telephone set, the combination with a hook switch of a signaling circuit, a listening circuit, and a talking circuit controlled'by said hook switch, said hook switch having three positions, said signaling circuit closed when the hook switch is in first position, means for moving said switch. hook from first to second position to open said signaling circuit and close said listening circuit, and for moving said hook switch from second to third position to render said listening circuit inoperative and to close said talking circuit.

8. In a substation telephone set, the combination with talking and listening circuits, and a hook switch for controlling the same, automatic means for stopping said hook switch in intermediate posltion when the receiver is removed, said listening circuit closed when the switch is in intermediate position, and means for moving said hook switch from intermediate to off normal position to render said listening circuit inop erative and close said talking circuit.

9. In a substation telephone set, the combination with talking, signaling and listening circuits, and a hook switch for controlling the same, automatic means forstopping said hook switch in intermediate position when the receiver is removed, said signaling circuit closed only in normal position of said hook switch, said listening circuit closed when the switch is in intermediate position, and means for moving said hook switch from intermediate to ofif normal position to render said listening circuit inoperative and close said talking circuit.

10. In a substation tele hone set, a hook switch having normal, 01'? normal and intermediate positions, transmitter and receiver circuits, open in normal position of said switch, means for closin a receiver circuit in intermediate position of the switch and for closing the transmitter circuit and a new receiver circuit only in its 011? normal position, a support on one end of said hook switch for holding said receiver, a lever pivoted to the opposite end of said switch hook, and a fixed sto in the path of-said lever for holding t e hook switch in intermediate position.

1s pressed out of engagement with the escutcheon.

12. The combination of an escutcheon, a telephone switch-hook extending therethrough and pivoted at one end, a pawl on said switch-hook for engaging said escutcheon whereby the switch-hook may be held in intermediate position, means for further raising the switch-hook when the call is pressed out of engagement with the escutcheon,. a line circuit associated with said switch-hook, a calling device for sending impulses over said line and a switch controlled by said switch-hook, whereby when the switch-hook is in intermediate position the calling device is inoperative for sending impulses over the line and when the switchbook is in said further raised position the f calling device is operatively connected to the line.

13. A Subscribers telephone set in combination with a telephone line, a condenser, 'an impulse sender in said set for sendlng a serles of lmpulses over said line, a switchhook, an automatic device for holding the s'witchin intermediate position when the receiver is removed and means for further raising the switch-hook thereafter, a switch controlled by said switch-hook whereby JOHN ERIoKsoN, 

